The filters in the entire purification system include formaldehyde removal filters, deodorization filters, dust collection filters and HEPA filters. Among them, the HEPA filter is composed of very fine organic fibers interwoven, which are continuously folded back and forth to form a wavy gasket. Due to its small pore size, the micro particles cannot pass through. It has large adsorption capacity, high purification efficiency, and has Water absorption and other characteristics. HEPA can be divided into five kinds of materials: Humidifier filters, H13 HEPA filters, composite PP PET filter paper, melt-blown polyester non-woven fabric and melt-blown glass fiber.

More layers are not necessarily better

As mentioned above, HEPA filter has a strong purification effect and is the most commonly used type of filter in air purifier products. In principle, the use of HEPA filter element to filter PM2.5 pollution particles has certain requirements on the density and thickness of the HEPA filter. The thicker the HEPA filter, the more layers it folds, and the better the air purification ability.

 However, the problem arises from this: the more layers of HEPA filters, the greater the wind resistance, and the higher the requirements for the air volume of the purifier, and sometimes the effect is not necessarily better.

On this issue, we have had in-depth discussions with technicians from many air purifier companies. They unanimously stated that if the length and width of the air purifier can carry the HEPA filter element in a fixed space, theoretically, the more folds of HEPA, the larger the expansion area and the better the effect. However, if there are too many HEPA folded layers, it will cause insufficient space for each fold of the HEPA filter, which will cause a large wind resistance and affect the actual purification effect. To solve the problem of wind resistance, it is necessary to increase the efficiency of the fan, but this will not only increase the power consumption of the whole machine, but also affect the service life of the fan to a certain extent.

It can be seen that data such as the number of HEPA folded layers and the efficiency of the fan will directly affect the CADR value of the air purifier. Therefore, at the beginning of the design, many air purifier companies will design a CADR value expected to be achieved in the early stage, or obtain the optimal number of folded layers of the HEPA net through data such as the efficiency of the fan and the space that can carry the HEPA net, or The efficiency of the fan is calculated through the estimated number of HEPA mesh folded layers. In short, only when the fan efficiency and the number of folded layers reach a certain balance, the CADR value can be achieved to an ideal level.